import {createApp, onMounted} from 'vue'
import App from './App.vue'
import router from './router'
import store from './store'
//1.引入element-plus组件库
import ElementPlus, {ElMessage} from 'element-plus'
import 'element-plus/dist/index.css'
//3.引入element-plus图标库
import * as ElementPlusIconsVue from '@element-plus/icons-vue'
//5.1修改elementPlus默认中文
import zhCn from 'element-plus/dist/locale/zh-cn.mjs'

//9.1 配置根路径
const BASE_URL = 'http://localhost:8080';
//window是全局对象，给它设置属性，此属性可以在任意script标签中使用！
window.BASE_URL = BASE_URL;

const app = createApp(App)
//9.2 给app 也就是vue实例也设置根路径，这样就可以在任意template标签中使用！
app.config.globalProperties.BASE_URL = BASE_URL;
//4.遍历ElementPlusIconsVue对象中的所有图标组件并注册到app中
for (const [key, component] of Object.entries(ElementPlusIconsVue)) {
    app.component(key, component)
}

//2.app.use(ElementPlus) 使用Element-plus组件库
//5.2 app.use(ElementPlus,{ locale: zhCn })将El本地化为中文
app.use(ElementPlus,{ locale: zhCn }).use(store).use(router).mount('#app')

//6.解决ResizeObserver Error
const debounce = (fn, delay) => {
    let timer = null;
    return function () {
        let context = this;
        let args = arguments;
        clearTimeout(timer);
        timer = setTimeout(function () {
            fn.apply(context, args);
        }, delay);
    }
}
const _ResizeObserver = window.ResizeObserver;
window.ResizeObserver = class ResizeObserver extends _ResizeObserver {
    constructor(callback) {
        callback = debounce(callback, 16);
        super(callback);
    }
}
//7.定义获取当前登录用户的全局方法
window.getUser=()=>{
    return localStorage.user ? JSON.parse(localStorage.user) :null;
}

//8.设置路由守卫:每次使用路由跳转前，要确保用户在访问其它页面时已经登录
//路由跳转前要执行的方法
router.beforeEach((to, from, next) =>{
    //从localStorage中获取user数据
    let user = localStorage.user;
    //如果去到的目标路径不是登录页或首页，且用户数据为空
    if(to.path !== '/login' && !user && to.path !=='/')
        //就重定向到登录页，且提示’请先登录'
        //query:{redirect:to.fullPath}
        //是将用户尝试访问的完整路径作为查询参数传递给登录页面http://localhost:9090/login?redirect=/user
        // query:{redirect:to.fullPath}重定向到登录页面
        next({path:'/login',query:{redirect:to.fullPath}},ElMessage.error('请先登录'))
    else
        next();//如果目标路径是登录或首页，或用户已登录，则允许路由跳转
})

